Today's Kastri is ancient Pandosia, the most important 8th-century BC colony of the Elians and capital of the state of Kassopaia. Built on a hill dominating the whole area, the city was surrounded by walls of around 360 m, with a total length of about 1,640 m, reinforced by 22 orthogonal towers, and had a population of around 10,000.
Philip II of Macedon took the city around 343/2 BC and handed it to the Epirots. Destroyed by the Romans in 167 BC, it was immediately chosen as the capital of the League of Epirots, with its own coinage. It began to decline around 31 BC with the foundation of Nikopolis. In addition to the ancient walls, a wall from the time of Justinian survives.
